Comparison of treatment effects between clear aligners and fixed appliances in patients treated with miniscrew-assisted molar distalization.

OBJECTIVES: The biomechanics in achieving molar distalization may differ between fixed appliances and clear aligners in the control of tooth movement. The objective of this study was to compare the treatment effects between clear aligners (CA) and fixed appliances (FA) in patients treated with miniscrew-assisted molar distalization. METHODS: The sample consisted of 46 subjects with mild-to-moderate crowding. A total of 22 patients treated with clear aligners (age, 25.66 ±â€…6.11 years old) and 24 patients treated with fixed appliances (age, 24.04 ±â€…4.95 years old) for miniscrew-assisted molar distalization were included in this study. The dental and skeletal changes were evaluated by the pre- and post-treatment lateral cephalograms. RESULTS: Significant changes were found with the vertical variables SN-OP angle (2.24 ±â€…3.22°, P < .05) and SN-MP angle (0.73 ±â€…1.15°, P < .05) for the FA group when compared with the CA group (SN-OP angle 0.41 ±â€…2.26° and SN-MP angle -0.21 ±â€…1.38°, P > .05). Both treatment groups achieved a 2-3 mm. molar distalization with significant intrusion of the upper molars. The CA group showed significantly less distal tipping of molars (U6^PP angle -2.29 ±â€…3.29° and L6^MP angle -2.92 ±â€…2.49°, P < .05) compared to the FA group (-5.24 ±â€…4.28° and -5.53 ±â€…5.03°, P < .05). In addition, significant retraction and lingual inclination of the upper and lower incisors were found in both groups. LIMITATIONS: The changes of tooth position were evaluated by 2D lateral cephalograms, not 3D measurements. CONCLUSIONS: Compared to fixed appliances, clear aligners seemed to have better control of vertical dimension and distal tipping of molars in patients treated with miniscrew-assisted molar distalization.

Single Nucleotide Polymorphisms in RUNX2 and BMP2 contributes to different vertical facial profile.

The vertical facial profile is a crucial factor for facial harmony with significant implications for both aesthetic satisfaction and orthodontic treatment planning. However, the role of single nucleotide polymorphisms (SNPs) in the development of vertical facial proportions is still poorly understood. This study aimed to investigate the potential impact of some SNPs in genes associated with craniofacial bone development on the establishment of different vertical facial profiles. Vertical facial profiles were assessed by two senior orthodontists through pre-treatment digital lateral cephalograms. The vertical facial profile type was determined by recommended measurement according to the American Board of Orthodontics. Healthy orthodontic patients were divided into the following groups: "Normodivergent" (control group), "Hyperdivergent" and "Hypodivergent". Patients with a history of orthodontic or facial surgical intervention were excluded. Genomic DNA extracted from saliva samples was used for the genotyping of 7 SNPs in RUNX2, BMP2, BMP4 and SMAD6 genes using real-time polymerase chain reactions (PCR). The genotype distribution between groups was evaluated by uni- and multivariate analysis adjusted by age (alpha = 5%). A total of 272 patients were included, 158 (58.1%) were "Normodivergent", 68 (25.0%) were "Hyperdivergent", and 46 (16.9%) were "Hypodivergent". The SNPs rs1200425 (RUNX2) and rs1005464 (BMP2) were associated with a hyperdivergent vertical profile in uni- and multivariate analysis (p-value < 0.05). Synergistic effect was observed when evaluating both SNPs rs1200425- rs1005464 simultaneously (Prevalence Ratio = 4.0; 95% Confidence Interval = 1.2-13.4; p-value = 0.022). In conclusion, this study supports a link between genetic factors and the establishment of vertical facial profiles. SNPs in RUNX2 and BMP2 genes were identified as potential contributors to hyperdivergent facial profiles.

Craniofacial identification standards: A review of reliability, reproducibility, and implementation.

There are numerous anatomical and anthropometrical standards that can be utilised for craniofacial analysis and identification. These standards originate from a wide variety of sources, such as orthodontic, maxillofacial, surgical, anatomical, anthropological and forensic literature, and numerous media have been employed to collect data from living and deceased subjects. With the development of clinical imaging and the enhanced technology associated with this field, multiple methods of data collection have become accessible, including Computed Tomography, Cone-Beam Computed Tomography, Magnetic Resonance Imaging, Radiographs, Three-dimensional Scanning, Photogrammetry and Ultrasound, alongside the more traditional in vivo methods, such as palpation and direct measurement, and cadaveric human dissection. Practitioners often struggle to identify the most appropriate standards and research results are frequently inconsistent adding to the confusion. This paper aims to clarify how practitioners can choose optimal standards, which standards are the most reliable and when to apply these standards for craniofacial identification. This paper describes the advantages and disadvantages of each mode of data collection and collates published research to review standards across different populations for each facial feature. This paper does not aim to be a practical instruction paper; since this field encompasses a wide range of 2D and 3D approaches (e.g., clay sculpture, sketch, automated, computer-modelling), the implementation of these standards is left to the individual practitioner.

Classification of Indonesian adult forensic gender using cephalometric radiography with VGG16 and VGG19: a Preliminary research.

BACKGROUND: The use of cephalometric pictures in dental radiology is widely acknowledged as a dependable technique for determining the gender of an individual. The Visual Geometry Group 16 (VGG16) and Visual Geometry Group 19 (VGG19) algorithms have been proven to be effective in image classification. OBJECTIVES: To acknowledge the importance of comprehending the complex procedures associated with the generation and adjustment of inputs in order to obtain precise outcomes using the VGG16 and VGG19 algorithms. MATERIAL AND METHOD: The current work utilised a dataset including 274 cephalometric radiographic pictures of adult Indonesians' oral health records to construct a gender classification model using the VGG16 and VGG19 architectures using Python. RESULT: The VGG16 model has a gender identification accuracy of 93% for females and 73% for males, resulting in an average accuracy of 89% across both genders. In the context of gender identification, the VGG19 model has been found to achieve an accuracy of 0.95% for females and 0.80% for men, resulting in an overall accuracy of 0.93% when considering both genders. CONCLUSION: The application of VGG16 and VGG19 models has played a significant role in identifying gender based on the study of cephalometric radiography. This application has demonstrated the exceptional effectiveness of both models in accurately predicting the gender of Indonesian adults.

Mapping an intelligent algorithm for predicting female adolescents' cervical vertebrae maturation stage with high recall and accuracy.

BACKGROUNDS AND OBJECTIVES: The present study was designed to define a novel algorithm capable of predicting female adolescents' cervical vertebrae maturation stage with high recall and accuracy. METHODS: A total of 560 female cephalograms were collected, and cephalograms with unclear vertebral shapes and deformed scales were removed. 480 films from female adolescents (mean age: 11.5 years; age range: 6-19 years) were used for the model development phase, and 80 subjects were randomly and stratified allocated to the validation cohort to further assess the model's performance. Derived significant predictive parameters from 15 anatomic points and 25 quantitative parameters of the second to fourth cervical vertebrae (C2-C4) to establish the ordinary logistic regression model. Evaluation metrics including precision, recall, and F1 score are employed to assess the efficacy of the models in each identified cervical vertebrae maturation stage (iCS). In cases of confusion and mispredictions, the model underwent modification to improve consistency. RESULTS: Four significant parameters, including chronological age, the ratio of D3 to AH3 (D3:AH3), anterosuperior angle of C4 (@4), and distance between C3lp and C4up (C3lp-C4up) were administered into the ordinary regression model. The primary predicting model that implements the novel algorithm was built and the performance evaluation with all stages of 93.96% for accuracy, 93.98% for precision, 93.98% for recall, and 93.95% for F1-score were obtained. Despite the hybrid logistic-based model achieving high accuracy, the unsatisfactory performance of stage estimation was noticed for iCS3 in the primary cohort (89.17%) and validation cohort (85.00%). Through bivariate logistic regression analysis, the posterior height of C4 (PH4) was further selected in the iCS3 to establish a corrected model, thus the evaluation metrics were upgraded to 95.83% and 90.00%, respectively. CONCLUSIONS: An unbiased and objective assessment of the cervical vertebrae maturation (CVM) method can function as a decision-support tool, assisting in the evaluation of the optimal timing for treatment in growing adults. Our novel proposed logistic model yielded individual formulas for each specific CVM stage and attained exceptional performance, indicating the capability to function as a benchmark for maturity evaluation in clinical craniofacial orthopedics for Chinese female adolescents.

Quantitative evaluation of vertical control in orthodontic camouflage treatment for skeletal class II with hyperdivergent facial type.

BACKGROUND: In this study, we sought to quantify the influence of vertical control assisted by a temporary anchorage device (TAD) on orthodontic treatment efficacy for skeletal class II patients with a hyperdivergent facial type and probe into the critical factors of profile improvement. METHODS: A total of 36 adult patients with skeletal class II and a hyperdivergent facial type were included in this retrospective case-control study. To exclude the effect of sagittal anchorage reinforcement, the patients were divided into two groups: a maxillary maximum anchorage (MMA) group (N = 17), in which TADs were only used to help with anterior tooth retraction, and the MMA with vertical control (MMA + VC) group (N = 19), for which TADs were also used to intrude the maxillary molars and incisors. The treatment outcome was evaluated using dental, skeletal, and soft-tissue-related parameters via a cephalometric analysis and cast superimposition. RESULTS: A significant decrease in ANB (P < 0.05 for both groups), the retraction and uprighting of the maxillary and mandibular incisors, and the retraction of protruded upper and lower lips were observed in both groups. Moreover, a significant intrusion of the maxillary molars was observed via the cephalometric analysis (- 1.56 ± 1.52 mm, P < 0.05) and cast superimposition (- 2.25 ± 1.03 mm, P < 0.05) of the MMA + VC group but not the MMA group, which resulted in a remarkable decrease in the mandibular plane angle (- 1.82 ± 1.38°, P < 0.05). The Z angle (15.25 ± 5.30°, P < 0.05) and Chin thickness (- 0.97 ± 0.45°, P < 0.05) also improved dramatically in the MMA + VC group, indicating a better profile and a relaxed mentalis. Multivariate regression showed that the improvement in the soft tissue was closely related to the counterclockwise rotation of the mandible plane (P < 0.05). CONCLUSIONS: TAD-assisted vertical control can achieve intrusion of approximately 2 mm for the upper first molars and induce mandibular counterclockwise rotation of approximately 1.8°. Moreover, it is especially important for patients without sufficient retraction of the upper incisors or a satisfactory chin shape.

Accuracy and reliability of magnetic resonance imaging in orthodontic diagnosis and treatment planning-a systematic review and meta-analysis.

BACKGROUND: Magnetic resonance imaging (MRI) is a non-ionizing imaging technique. Using MRI in dentistry may potentially lower the general radiation dose of the examined population, provided MRI can replace various radiation-based images. Furthermore, novel MRI imaging modalities for three-dimensional and two-dimensional cephalometrics have recently been developed for orthodontic diagnosis. OBJECTIVES: This systematic review aimed to determine the diagnostic accuracy and reliability of MRI in orthodontic diagnosis and treatment planning. SEARCH METHODS: An electronic search was conducted on 20 November 2022 in the following databases: PubMed, LILACS, Web of Science, EMBASE, Scopus, and Cochrane. The search was updated on 30 August 2023. Furthermore, a grey literature search was performed in Google Scholar and Open-Grey. SELECTION CRITERIA: This review included descriptive, observational, cohort studies, cross-sectional, case-control studies, and randomized/non-randomized trials related to the research question. The study excluded studies related to patients with syndromes, chronic diseases, craniofacial anomalies, or bone diseases. DATA COLLECTION AND ANALYSIS: The included studies were quality assessed using the "Joanna Brigg's Critical Appraisal Tool for diagnostic test accuracy". The GRADE approach for non-randomized studies was used for strength-of-evidence analysis. RESULTS: Eight of the 10 included studies compared MRI with either cone beam computed tomography or lateral cephalogram and found a high intra- and inter-rater agreement for landmark identification. The risk of bias was high in four studies, moderate in three, and low in three studies. Homogeneity was lacking among the included studies in terms of MRI imaging parameters and sample characteristics. This should be taken into consideration by future studies where uniformity with respect to these parameters may be considered. CONCLUSIONS: Despite dissimilarity and heterogeneity in the sample population and other methodological aspects, all the included studies concluded that MRI enjoyed considerable intra- and inter-examiner reliability and was comparable to current diagnostic standards in orthodontics. Furthermore, the studies agreed on the innovative potential of MRI in radiation-free diagnosis and treatment planning in orthodontics in the future. REGISTRATION: CRD number: CRD420223XXXXX.

Relationship between bite force, occlusal contact area, and three-dimensional facial soft tissue in dentofacial deformities.

PURPOSE: This study aimed to investigate three-dimensional facial soft tissue dimensions, maximum bite force (MBF), and occlusal contact area in patients with DFD. In addition, we analyzed the relationship between MBF and the three-dimensional facial measurements. METHODS: Thirty-two patients with skeletal Class III DFD and 20 patients with Class II DFD underwent a soft tissue evaluation using surface laser scanning, as well as MBF and occlusal contact area assessments. The DFD groups were compared with each other and with 25 healthy subjects. RESULTS: Significant morphological differences were found in the transversal, vertical, and anteroposterior dimensions between Class II DFD and Class III DFD. Both DFD groups presented an increased linear distance of chin height, which was strongly related with decreased MBF magnitude. The DFD groups exhibited lower MBF and occlusal contact area, with no significant differences between Class II and Class III DFD. CONCLUSION: The presence of DFD affected 3D measurements of facial soft tissue, causing variations beyond normal limits, lower MBF, and occlusal contact area in both Class II and Class III DFD patients. The vertical dimension might have influenced the lower MBF magnitude in the studied skeletal deformities.

Effects of adenoid hypertrophy on nasopharyngeal airway ventilation: A computational fluid dynamics study.

OBJECTIVES: Adenoid hypertrophy causes impaired nasopharyngeal airways (NA) ventilation. However, it is difficult to evaluate the ventilatory conditions of NA. Therefore, this study aimed to analyze the nasopharyngeal airway resistance (NARES) based on computational fluid dynamics simulations and the nasopharyngeal airway depth (NAD) and adenoid hypertrophy grade measured on cephalometric cone-beam computed tomography images and determine the relationship between NAD and grade and NARES to ultimately assess using cephalometric measurements whether NA has airway obstruction defects. METHODS: Cephalogram images were generated from cone-beam computed tomography data of 102 children (41 boys; mean age: 9.14 ± 1.43 years) who received orthodontic examinations at an orthodontic clinic from September 2012 to March 2023, and NAD and adenoid grade and NARES values were measured based on computational fluid dynamics analyses using a 3D NA model. Nonlinear regression analyses were used to evaluate the relationship between NARES and NAD and correlation coefficients to evaluate the relationship between grade and NARES. RESULTS: NARES was inversely proportional to the cube of NAD (R2 = 0.786, P < 0.001), indicating a significant relationship between these variables. The resistance NARES increased substantially when the distance NAD was less than 5 mm. However, adenoid Grade 4 (75 % hypertrophy) was widely distributed. CONCLUSIONS: These study findings demonstrate that the ventilatory conditions of NA can be determined based on a simple evaluation of cephalogram images. An NAD of less than 5 mm on cephalometric images results in NA obstruction with substantially increased airflow resistance.

Comparative cephalometric study of the airways between different ethnic groups with normal occlusion.

OBJECTIVE: This study aimed to compare the nasopharynx and oropharynx airway dimensions of Caucasians, Blacks, Japanese, Japanese Brazilians, and Black Caucasians. METHODS: A sample of 216 lateral radiographs of untreated young Brazilian subjects (mean age of 12.94 years; SD 0.88) were divided into five groups: Black Caucasian, Black, Caucasian, Japanese, and Japanese Brazilian. Lateral radiographs were used to measure the oropharynx (from the midpoint on the soft palate to the closest point on the anterior pharyngeal wall) and the nasopharynx (from the intersection of the posterior border of the tongue and the inferior border of the mandible to the closest point on the posterior pharyngeal wall). Analyses of variance (ANOVA) and Tukey's test were performed (p< 0.05). RESULTS: The linear dimension of the oropharynx was similar among the different ethnic groups. Caucasian individuals presented a significantly greater linear dimension of the nasopharynx than Black Caucasian and Black individuals. CONCLUSIONS: All the groups had similar buccopharyngeal values. However, Caucasian individuals had significantly higher values when compared to Black Caucasians and Black individuals.

Automatic extraction of facial median sagittal plane for patients with asymmetry based on the EDMA alignment algorithm.

BACKGROUND: We aimed to establish a novel method for automatically constructing three-dimensional (3D) median sagittal plane (MSP) for mandibular deviation patients, which can increase the efficiency of aesthetic evaluating treatment progress. We developed a Euclidean weighted Procrustes analysis (EWPA) algorithm for extracting 3D facial MSP based on the Euclidean distance matrix analysis, automatically assigning weight to facial anatomical landmarks. METHODS: Forty patients with mandibular deviation were recruited, and the Procrustes analysis (PA) algorithm based on the original mirror alignment and EWPA algorithm developed in this study were used to construct the MSP of each facial model of the patient as experimental groups 1 and 2, respectively. The expert-defined regional iterative closest point algorithm was used to construct the MSP as the reference group. The angle errors of the two experimental groups were compared to those of the reference group to evaluate their clinical suitability. RESULTS: The angle errors of the MSP constructed by the two EWPA and PA algorithms for the 40 patients were 1.39 ± 0.85°, 1.39 ± 0.78°, and 1.91 ± 0.80°, respectively. The two EWPA algorithms performed best in patients with moderate facial asymmetry, and in patients with severe facial asymmetry, the angle error was below 2°, which was a significant improvement over the PA algorithm. CONCLUSIONS: The clinical application of the EWPA algorithm based on 3D facial morphological analysis for constructing a 3D facial MSP for patients with mandibular deviated facial asymmetry deformity showed a significant improvement over the conventional PA algorithm and achieved the effect of a dental clinical expert-level diagnostic strategy.

Establishment of the mid-sagittal reference plane for three-dimensional assessment of facial asymmetry: a systematic review : Establishment of the mid-sagittal reference plane: a systematic review.

OBJECTIVE: To systematically review the literature for mid-sagittal plane establishment approaches to identify the most effective method for constructing the mid-sagittal plane for the evaluation of facial asymmetry. MATERIALS AND METHODS: Six electronic databases (PubMed, Medline (via Ovid), EMBASE (via Ovid), Cochrane Library, Web of Science, and Scopus) and grey literature were searched for the studies that computed the mid-sagittal reference plane three-dimensionally, using a combination of MeSH terms and keywords. The methodological quality and the level of evidence for the included studies were analyzed using QUADAS-2 and GRADE, respectively. RESULTS: The preliminary search yielded 6746 records, of which 42 articles that met the predefined inclusion criteria were included in the final analysis. All the included articles reported the construction of the mid-sagittal reference plane (MSP) using varied methods. The risk of bias and concerns regarding the applicability of the included studies were judged to be 'low'. The level of evidence was determined to be 'low' for the effectiveness of the technique and 'moderate' for the ease of clinical applicability. CONCLUSION: Despite methodological heterogeneity, this review substantiates the comparable efficacy of cephalometric and morphometric MSP construction methods. A fully automated morphometric MSP holds promise as a viable option for routine clinical use. Nevertheless, future prospective studies with an emphasis on the impact, accuracy, and clinical applicability of MSP construction techniques in cases of facial asymmetry are required. CLINICAL RELEVANCE: The present review will assist clinicians in selecting the most suitable method for MSP construction, leading to improved treatment planning and ultimately more favorable treatment outcomes.

CORRELATION BETWEEN TRANSVERSE CEPHALOMETRIC PARAMETERS AND THE SEVERITY OF SKELETAL MALOCCLUSIONS.

Malocclusion prevalence varies globally, ranging from 34.9% to 93.6% for Class I, 4.4% to 44.7% for Class II, and 1.4% to 19.4% for Class III occlusions. This study aims to assess transverse cephalometric measurements related to maxillary and mandibular dimensions, intermolar and intercanine distances, and other relevant factors. The descriptive cross-sectional research included 100 individuals with malocclusion grades 1, 2, and 3. The study involved 100 participants across three age groups (15-21, 22-28, 29-35), with the majority in the 22-28 range. Gender distribution showed a significant imbalance (77% female, 23% male). Cephalometric measurements for three malocclusion types revealed distinct patterns. Notably, inter-molar width exhibited a strong positive correlation with malocclusion severity (Malocclusion 1: r=0.504 to 0.561, Malocclusion 2: r=0.560 to 0.625, Malocclusion 3: r=0.625 to 0.559), while maxillary-mandibular transverse discrepancy had a negative correlation (Malocclusion 1: r=-0.496, Malocclusion 2: r=-0.483, Malocclusion 3: r=-0.483). Age-diverse sample, gender imbalance noted. Cephalometric correlations reveal inter-molar width association with malocclusion severity, emphasizing clinical implications.

Comparison of PAS and adenoids in patients with and without maxillary micrognathia before orthodontic treatment.

OBJECTIVE: Craniofacial anomalies are widely discussed as predisposing factors of breathing disorders. Since many more cofactors exist, this study investigated the association between maxillary micrognathia and morphological changes of posterior airway space and adenoids in these patients. MATERIAL AND METHODS: Cephalometric radiographs of n = 73 patients were used for data acquisition. The patients were divided into two groups according to certain skeletal characteristics: maxillary micrognathia (n = 34, 16 female, 18 male; mean age 10.55 ± 3.03 years; defined by a SNA angle < 79°) and maxillary eugnathia (n = 39, 19 female, 20 male; mean age 10.93 ± 3.26 years; defined by a SNA angle > 79°). The evaluation included established procedures for measurements of the maxilla, posterior airway space and adenoids. Statistics included Kolmogorov-Smirnov-, T- and Mann-Whitney-U-Tests for the radiographs. The level of significance was set at p < 0.05. RESULTS: The cephalometric analysis showed differences in the superior posterior face height and the depth of the posterior airway space at palatal level among the two groups. The depth of the posterior airway space at mandibular level was the same for both groups, just as the size of the area taken by adenoids in the nasopharynx. CONCLUSIONS: Skeletal anomalies affect the dimension of the posterior airway space. There were differences among the subjects with maxillary micrognathia and these with a normal maxilla. However, the maxilla was only assessed in the sagittal direction, not in the transverse. This study showed that the morphology of the maxilla relates to the posterior airway space whereas the adenoids seem not to be affected. CLINICAL RELEVANCE: Maxillary micrognathia is significantly associated with a smaller depth of the posterior airway space at the palatal level compared to patients with maxillary eugnathia.

Assessment of cephalometric parameters and correlation with the severity of the obstructive sleep apnea syndrome.

BACKGROUND: In individuals diagnosed with obstructive sleep apnea syndrome (OSAS), variations in craniofacial structure have been inconsistently documented, showing differing degrees of alteration between obese and nonobese patients. In addition, sleep disturbance has also been shown to induce disequilibrium in this population of patients. This pilot observational study aimed to assess craniofacial values in obese and nonobese subpopulations of patients with OSAS and their correlation and association with the severity of OSAS. We also assessed whether OSAS patients are characterized by an impaired equilibrium in relation to and associated with the severity of OSAS. METHODS: We included all consecutive adult patients with OSAS. Through cephalometry, we assessed the upper (UPa-UPp) and lower (LPa-LPp) pharynx diameters, superior anterior facial height (Sor-ANS), anterior facial height (ANS-Me), anterior vertical dimension (Sor-Me), posterior facial height (S-Go) and craniovertebral angle (CVA). Furthermore, we analyzed postural equilibrium through a stabilometric examination. RESULTS: Forty consecutive OSAS patients (45% female with a mean age of 56 ± 8.2 years) were included. The subgroup of nonobese patients had a reduced UPa-UPp (p = 0.02). Cephalometric measurements were correlated with the severity of OSAS in nonobese patients, whereas only Sor-ANS was correlated with the severity of OSAS in the obese subpopulation. In the overall population, altered craniofacial values are associated with severe OSAS. Although there are differences in equilibrium between obese and nonobese OSAS patients, the stabilometric measurements were not correlated or associated with OSAS severity. CONCLUSION: Altered craniofacial values and compromised equilibrium in OSAS patients are linked to OSAS severity. Therefore, the management of OSAS should be tailored not only to weight management but also to craniofacial and postural rehabilitation to enhance patient outcomes.

Basal and dentoalveolar transverse parameters in different sagittal and vertical malocclusions in adults: a comparative study.

OBJECTIVE: This study sought to three-dimensionally (3D) evaluate the maxillomandibular basal bone and dentoalveolar widths using cone-beam computed tomography (CBCT) scans in adult Chinese populations with different vertical and sagittal facial skeletal patterns whilst no apparent posterior dental crossbite. MATERIALS AND METHODS: The retrospective cross-sectional comparative study enrolled CBCT images of 259 adult patients (125 males and 134 females). The subjects were divided into the hyperdivergent(n = 82), hypodivergent(n = 88), and normodivergent(n = 89) groups based on the Jarabak ratio (S-GO/N-Me), which were further divided into three subgroups of skeletal Class I, II and III, based on both the ANB angle and AF-BF parameters. ANOVA was used to analyze the extracted data of the studied groups. The intra- and inter-observer reliability was analyzed using the intra-class correlation coefficient (ICC). RESULTS: In all three vertical facial skeletal patterns, the skeletal Class II had significantly smaller mandibular basal bone width compared to skeletal Class I and Class III, both at the first molar and first premolar levels. The skeletal Class III seemed to have smaller maxillary basal bone width compared to skeletal Class I and Class II malocclusions; however, a significant difference was found only in the normodivergent pattern. As for the dentoalveolar compensation, it was most notable that in the hypodivergent growth pattern, the skeletal Class II had significantly smaller maxillary dentoalveolar width compared to the Class I and Class III groups, both at the first molar and first premolar levels. CONCLUSIONS: Based on the sample in the present study, skeletal Class II has the narrowest mandibular basal bone regardless of the vertical facial skeletal pattern. CLINICAL RELEVANCE: For Chinese adults with no apparent transverse discrepancy, the maxillomandibular basal bone and dentoalveolar widths are revealed in specific categories based on different vertical and sagittal facial skeletal patterns. In diagnosis and treatment planning, particular attention should be paid to skeletal Class II for possibly existing mandibular narrowing.

Comparison of different maxillary advancement protocols in patients with unilateral cleft lip and palate: a finite element analysis.

OBJECTIVES: The aim of this study was to evaluate the stress distributions and possible amount of movement in the maxillofacial region resulting from different maxillary advancement protocols in patients with unilateral cleft lip and palate. MATERIALS AND METHODS: A unilateral cleft lip and palate model (CLP model) with Goslon score 4 was created for finite element analysis. Three different protocols were compared: Group 1: usage of a face mask with elastics placed at a 30? angle to the occlusal plane over a conventional acrylic plate; Group 2: usage of a face mask with elastics placed at a 30? angle to the occlusal plane over miniplates placed in the infrazygomatic crest region; Group 3: usage of elastic from the menton plate placed in the mandible to the infrazygomatic plates in the maxilla. RESULTS: Dental effects were greater in the maxillary protraction protocol with a face mask over a conventional acrylic plate (Von Misses Stress Values; Group 1?=?cleft side:0.076, non-cleft side:0.077; Group 2?=?cleft side:0.004, non-cleft side: 0.003; Group 3?=?cleft side:0.0025; non-cleft side:0.0015), whereas skeletal effects were greater in maxillary protraction protocols with face mask using skeletal anchorage (Von Misses Stress Values; Group 1:0.008; Group 2:0.02; Group 3:0.0025). The maximum amount of counterclockwise rotation of the maxilla as a result of protraction was observed in traditional acrylic plate face mask protocol, and the minimum amount was observed by using elastics between infrazygomatic plates and menton plate. CONCLUSIONS: In individuals with unilateral cleft lip and palate with Goslon score 4, it was observed that the skeletally anchored face mask caused more skeletal impact and displacement than both the traditional acrylic plate face mask model and the pure skeletally supported maxillary protraction model. CLINICAL RELEVANCE: When planning maxillary protraction treatment in patients with cleft lip and palate, it should be considered that more movement in the sagittal plane might be expected on the cleft side than the non-cleft side, and miniplate and screws on the cleft side are exposed to more stress when using infrazygomatic plates as skeletal anchorage.

Skeletal, dentoalveolar and soft tissue changes after stabilization splint treatment for patients with temporomandibular joint disorders.

BACKGROUND: Temporomandibular disorder (TMD) is a grouping of heterogeneous disorders with multifactorial origins. Stabilization splints (SS) have demonstrated an acceptable treatment effect in TMD. The possible changes at the skeletal, dental, and soft tissue levels need to be addressed to evaluate the benefit/risk ratio of this therapeutic procedure. Accordingly, this study aimed to three­dimensionally evaluate skeletal, dentoalveolar and soft tissue changes after SS treatment for patients with TMD. METHODS: This retrospective study included 74 adult patients with myofascial and/or intra-articular disorders (25 males and 49 females), with an average age of 22.88 ± 4.8 years, who underwent SS treatment. Pre- and post-treatment Cone beam computed tomography were analysed using Invivo 6.0.3 software. The primary outcome was the vertical skeletal and dentoalveolar changes, while the secondary outcomes were the anteroposterior skeletal, dentoalveolar and soft tissue changes. Paired t-test and Wilcoxon rank sum test were used for statistical analyses. RESULTS: For the primary outcome; skeletally, there was a significant increase in mandibular plane inclination (difference: 0.82°±1.37), decrease facial height ratio (difference: 0.45%±1.07) and at the dentoalveolar level, the inclination of the functional (FOP-SN, FOP-FH) and bisecting (BOP-SN, BOP-FH) occlusal planes exhibited a significant increase too (difference: 0.38 ± 1.43°, 0.49 ± 1.62°, 0.44 ± 1.29° and 0.41 ± 1.17°, respectively) and also a decrease in the overbite (difference: -0.54 ± 0.83). For the secondary outcomes; there was a significant decrease in mandibular position (SNB) (difference: 1.60 ± 1.36°) and increase in the overjet (difference: 0.93 ± 1.04, p < 0.001) and a significant lower lip retrusion (difference: 0.33 ± 1.01 mm p < 0.01), was observed too. CONCLUSIONS: SS therapy resulted in significant vertical skeletal and dentoalveolar changes that were manifested mainly by facial height ratio, mandibular and occlusal plane changes, and to a lesser extent, significant anteroposterior skeletal, dentoalveolar, and soft tissue changes in the form of mandibular position, increased overjet and a more retrusive lower lip. These changes should be considered during patients' selection prior to initiating SS therapy.

Mandibular and dental measurements for sex determination using machine learning.

The present study tested the combination of mandibular and dental dimensions for sex determination using machine learning. Lateral cephalograms and dental casts were used to obtain mandibular and mesio-distal permanent teeth dimensions, respectively. Univariate statistics was used for variables selection for the supervised machine learning model (alpha = 0.05). The following algorithms were trained: logistic regression, gradient boosting classifier, k-nearest neighbors, support vector machine, multilayer perceptron classifier, decision tree, and random forest classifier. A threefold cross-validation approach was adopted to validate each model. The areas under the curve (AUC) were computed, and ROC curves were constructed. Three mandibular-related measurements and eight dental size-related dimensions were used to train the machine learning models using data from 108 individuals. The mandibular ramus height and the lower first molar mesio-distal size exhibited the greatest predictive capability in most of the evaluated models. The accuracy of the models varied from 0.64 to 0.74 in the cross-validation stage, and from 0.58 to 0.79 when testing the data. The logistic regression model exhibited the highest performance (AUC = 0.84). Despite the limitations of this study, the results seem to show that the integration of mandibular and dental dimensions for sex prediction would be a promising approach, emphasizing the potential of machine learning techniques as valuable tools for this purpose.